Lyso-phosphatidylcholine (LPC) acyltransferase mediates the sn-2 acylation of LPC to produce phosphatidylcholine (PC). This enzyme represents a key component in the acyl group remodeling of phospholipid molecules. Active phospholipid remodeling may limit the accumulation of fatty acids into oil, and thus seed oil content, because the metabolic process of phospholipid deacylation and reacylation is considered a metabolic futile cycle. Acyl-remodeling is also implicated in the deposition of unusual fatty acids into storage lipids. Unusual fatty acid is a term used for fatty acid molecules that are not normally found in oilseed crops. Unusual fatty acids include hydroxyl fatty acids, very long chain fatty acids, short chain and medium short chain fatty acids, conjugated fatty acids, polyenoic fatty acids, epoxy fatty acids, acetylenic acids, etc. Because of a lack of understanding of acyl remodeling, efforts aimed at producing unusual fatty acids for industrial feedstock has met difficulty in reaching a level of commercial significance.
International Patent Application PCT/US2007/025650 filed Dec. 13, 2007 and U.S. patent application Ser. No. 11/820,014 filed Jun. 15, 2007 (Zou et al., 2007) disclose lyso-phosphatidylcholine acyltransferase (LPCAT) genes from yeast, plant and human. They further disclose that expression or over-expression of these genes in a cell modulates or enhances production of fatty acids, especially polyunsaturated fatty acids (PUFA) or other unusual fatty acids, and/or increases oil content in the cell. They further disclose a yeast mutant strain in which the gene, YOR175c, was knocked out thereby reducing LPCAT activity in the yeast. However, there is no report on the effect of reducing LPCAT activity on oil content and fatty acid levels.
Further, the function of the LPCAT gene in glycerolipid metabolism has been previously described (Chen 2007). However, this report did not describe the effect of reducing LPCAT activity on oil content and fatty acid levels.